When should I test?

So I'm about a week past my period.. I took a test a few days ago and got what I thought was a vvvfl, but two tests afterwards both gave me a bfn..

As of now, I don't have many symptoms. I keep getting super nauseous during car rides and I'm getting exhausted from small things such as going upstairs or putting away groceries. Even cleaning makes me nauseous. And I'm super emotional and anxious. But I'm not sure if that's related to my already existing anxiety and major depression. No other possible symptoms though..

My hubby thinks I am, and he bought me two brands of tests.. but I don't want to waste another test. Those damn things are expensive. And I don't want to get another dissapointing negative result.

So when should I test?